Hay conditioners generally include a pair of rollers mounted in co-extensive parallel relationship for rotation about respective axes with the crop arranged to pass between the rollers in a conditioning action.
Each of the rollers generally carries a plurality of longitudinally extending angularly spaced flutes which project outwardly from the surface of the roller. The rollers are spaced by a set distance at the nip such that the flutes intermesh generally without contact between the rollers. The intermeshing of the flutes causes the crop material to be bent as it passes between the rollers causing a cracking of the waxy surface of the crop stem.
It is necessary in such rollers to allow one of the rollers, generally the top roller, to move in a direction to increase the width of the nip by increasing the spacing between the axes of the rollers, to accommodate different amounts of crop material passing between the rollers and to accommodate obstacles such as stones and sticks which pass through without causing damage to the rollers. Generally this movement is provided by carrying each end of the top roller on a pivot arm or pivot plate which allows pivotal movement about an axis parallel to the axis of the roller together with a spring biasing system which applies tension to the top roller acting to close the nip while allowing each end independently to rise and lower in a floating action.
U.S. Pat. No. 7,188,461 (Fox) assigned to the present assignee and issued Mar. 13, 2007 discloses an arrangement of this type where the top roller is spring biased downwardly into contact with the crop by a pair of springs operating at opposite ends of the top roller. Each spring is mounted within a transverse beam across the conditioner. The springs extend from an inner end carried on a bracket attached to the beam to an outer end which carries a threaded rod which extends from the outer end of the spring to the outer end of a pivotal link. Thus the spring pulls inwardly holding the structure in the closed position. In the event that the link is pivoted outwardly by lifting of the end of the roller, the rod is moved outwardly thus tensioning the spring.
U.S. Pat. No. 5,022,219 (Knurr) assigned to Gehl and issued Jun. 11, 1991 discloses an arrangement of this type where a conditioner having first and second conditioning rolls, one of which is movably mounted, includes a mounting system for selectively urging the movable roll toward the other roll. The mounting system includes a pair of mounting plates adapted for placement one on either side of the movable roll, with the mounting plates being pivotally mounted to a frame. A hydraulically operated adjustment arrangement is connected to the mounting plates to relieve the biasing force exerted on the mounting plates, thus allowing movement of the movable roll away from the other roll to accommodate passage of a mass of material therethrough.
U.S. Pat. No. 4,896,483 (O'Halloran) assigned to Hay and Forage and issued Jan. 30, 1990 discloses a crop conditioner having a frame and first and second rolls each rotatable about an axis of rotation. A mounting assembly for the first roll includes a sub-assembly at each end of the first roll which permit the first roll to be pivoted relative to the second roll. Each sub-assembly has a mounting plate rotatably supporting one end of the first roll and supported on the frame for pivotal movement about a pivot axis which is generally parallel to and displaced from the axis of rotation of the first roll such that the axis of rotation of the first roll is movable relative to the axis of rotation of the second roll between a first position, a second position and a third position. The second and third positions of the first roll are progressively farther away from the axis of rotation of the second roll than the first position. A spring extending generally parallel to the axis of the rolls exerts a biasing force on the mounting plate through a cam plate to press the first roll toward the second roll. The spring and cam plate are arranged so that the biasing force has a magnitude which is less when the first roll is located between the second and third positions than when the first roll is located between the first and second positions.
U.S. Pat. No. 4,472,927 (Vogt) assigned to Deere and issued Sep. 25, 1984 discloses a hay conditioner of typical construction which discloses very schematically a spring for tensioning the top roll onto the bottom roll through a bell crank and a link. The upper roll is free to move upwardly in response to crops passing between the rolls, but its downward movement is limited to the stopped position selected by an adjustment link with the link extending upwardly to a free end that is accessible to receive a wrench.
U.S. Pat. No. 4,516,392 (McLean) assigned to Sperry New Holland and issued May 14, 1995 discloses a mower-conditioner having a pair of rotatable conditioning rolls where the bearings rotatably supporting each conditioning roll are recessed into the end of the conditioning roll.